Mapping technical façade elements under low-intensity seismicity to support risk-informed urban decision-making

Building façades constitute a critical spatial interface between urban open spaces and their users, where technical façade elements (TFEs) directly mediate everyday safety conditions. This is especially evident in historic urban areas, where tourist exposure is higher. Despite growing evidence from recent earthquakes, façade-related components remain largely underrepresented in conventional seismic risk frameworks, particularly under low-intensity and low-to-moderate seismicity, where cumulative damage processes and environmental degradation can increase outdoor vulnerability. This study proposes an operational framework for the systematic characterisation, qualification and spatialisation of façade-related TFEs, to support preventive decision-making. The methodology is grounded in two complementary knowledge sources: (i) the critical integration of regulatory and technical references, used to define a unified taxonomy and catalogue of façade elements; and (ii) the comparative analysis of real damage patterns observed during recent seismic events. This empirical analysis supports the identification of prevalent vulnerability patterns across different TFEs, and specifically elements exhibiting early sensitivity under low-intensity seismic actions. The classified TFEs and their associated attributes are structured into a minimum dataset for implementation within a GIS-based environment, enabling georeferenced mapping and aggregation of façade-related vulnerabilities. Therefore, element typologies, relative importance and prevalent damage classes are combined into a coherent qualitative classification system. This enables the rapid identification of potential critical façade elements without reliance on complex numerical modelling. Furthermore, the spatialised information provides a valuable decision-support layer for policymakers, facilitating the identification of urban open sub-areas characterised by reduced safety levels for users in outdoor. Overall, the systematisation and assessment of outcomes from façade to district scale offer a scalable and transferable tool for urban surveys, supporting the prioritisation of recurring vulnerability classes within façade element taxonomies. The framework is finally tested in a historic urban context, demonstrating its capability to capture differentiated vulnerability patterns across façade fronts.